By Andrew Nikiforuk, InsideClimate News

For this reason, the world's largest energy project will likely dominate political discussions between Canada and the United States for a long time.

Seven years ago, Canada quietly surpassed Saudi Arabia as the United States' major supplier of oil by rapidly exploiting shallow deposits of a tarry bitumen that industry calls "difficult oil." This badly degraded, unconventional resource has little market value unless extensively upgraded and refined. It won't even move through a pipeline without being diluted by light oil.

A switch from bloody light oil to dirty heavy oil has many defenders. For starters, Canada's tar sands, the world's second-largest petroleum reserve, are a vast and secure resource. No money spent on Canadian bitumen would be redirected to fundamentalist sects or Middle East insurgencies.

But replacing Saudia Arabia's tainted light oil with bitumen is no direct pipeline to energy security. It's more like switching your family's mortgage from Countrywide Financial to Bear Stearns.

The million-barrel-a-day project, which produces the world's most expensive oil, is creating monstrous environmental problems. While dinosaur-sized shovels and trucks excavate city-sized mines, energy-guzzling steam operations must heat up deeper formations to 500 degrees Fahrenheit. Since the 1970s the open-pit mines have moved enough earth to build seven Panama Canals.

Incredibly, the steam operations will consume nearly $200 billion worth of natural gas in the next decade and now threaten groundwater throughout the world's third-largest watershed.

One of the biggest costs of bitumen extraction remains toxic waste. The bitumen mines make ungodly lakes of pollution that are as poorly regulated as coal-mine tailings in the United States. Today, more than a dozen toxic ponds—among the world's largest impoundments of such waste—now occupy both sides of the Athabasca River.

They contain bitumen, phenols, polycyclic aromatic hydrocarbons, cyanide, and naphthenic acids (carcinogens and fish killers all). When I wrote Tar Sands, these ponds occupied 23 square miles of forest along the Athabasca River. They now cover 50 square miles and contain enough sludge to fill 300 Love Canals. Even Canada's timid National Energy Board calls the buildup of these leaky ponds "daunting."

Unlike oil from Texas or the North Sea, bitumen contains a hellish number of carbon atoms and requires prodigious amounts of energy to produce.

Although no agency or government has yet done a reliable study on mine-to-car emissions from the tar sands, industry experts have a good idea. They estimate that North Sea oil has a carbon dioxide footprint of about 20 pounds per barrel. In contrast, bitumen wrenched from the boreal forest ranges from 100 to 650 pounds of carbon dioxide per barrel.

Meanwhile, the carbon intensity of the $200 billion project has paralyzed the Canadian government. It now behaves much like the Bush-Cheney administration or as apologists for climate change deniers.

In the last ten years, Canada has spent $6 billion on climate change programs but not met a single target. The tar sands now emit more carbon than the entire nation of New Zealand. In the absence of any national energy plan or even renewable energy targets, Canada has placed all of its hopes on an expensive and unproven funeral service: carbon capture and storage.

Bitumen also eats water. Production of one barrel of bitumen requires approximately three barrels of Athabasca River water. A report issued last year by the U.S. Congress questioned whether there was enough water to keep the river healthy or "meet future needs of ... industry."

The project, which plans to grow to 3 million barrels a day, now runs on natural gas as a feed stock. Every day, the steam plants in the tar sands gobble enough of the blue flame to warm 6 million Canadian homes. In many ways, Canada is now sacrificing its energy security to fuel a continental addiction. Many industry executives bluntly compare the use of natural gas in bitumen production to burning all the Picassos in a museum in order to keep the visitors warm.

Global investors, environmentalists, aboriginals, and Canadian auditors are asking hard questions about the unconventional water, energy, and carbon footprint of bitumen. The U.S. Congress recognizes that environmental liabilities attending Canada's tar sands extraction might well curtail excavation of the poorer-grade deposits in nearby Utah.

In the end, Canada's tar sands won't solve any of America's critical energy problems or fund a greener and more independent economy. But for the short term, the future of tar sands production really rests in the hands of U.S. policymakers and consumers.

America's appetite for oil will likely determine the pace and scale of tar sands production.

With undisciplined consumption, the American people will accelerate and expand this environmental freak show in much the same way they funded Saudi extremism. But if they limit their use, gasoline buyers could transform the project into a temporary supply while the continent rapidly renews its economy with green power.

President Obama faces a stark choice: either end the United States' slavery to oil or became a slave to the tar sands. If America is serious about lessening its deadly dependence on oil, dirty or bloody, then U.S. dollars must support green energy.